Non-belspo (2002-2006)

Canadian Arctic Shelf Exchange Study (CASES)
on the thieme of microbial communities

Project description

The CASES subprogram on microbial
communities will examine the microbial communities and processes
which characterise the two types of environment, and the implications
for community structure and organic matter processing under the
two polynya scenarios (P1 and P2). The partners will measure
rates of microbial heterotrophy to assess the phototrophic-heterotrophic
balance across the study region and will examine the size distribution
and particle association of microheterotrophs (including protists)
that influence the fate of microbial production. They will determine
the temporal variations in microbial community structure (viruses,
bacteria, picocyanobacteria and protists) that are likely to
affect organic matter fluxes; these measurements will be conducted
at weekly intervals at the polynya and delta sites, with two
synoptic transects that will include sampling across the freshwater-saltwater
transition of the Mackenzie River. They will experimentally evaluate
the influence of light (open water versus ice cover) on microbial
community structure and processes; and the relative importance
of viral lysis versus microzooplankton grazing on the picoplankton
as two mechanisms of organic matter processing that regulate
the offshore export of particulate carbon.

In this theme, the Ulg
laboratory studies the genetic diversity of picocyanobacteria
found in the McKenzie River, its estuary and the Arctic Sea.
A 3-month travel grant from the ESF programme CYANOFIX allowed
Dr M. Waleron to work on this subject.